Radiology notes
Purpose and technique (50%)
A. Purpose of radiographic images
Describe the purpose of radiographic image
A. Periapical- is used to examine the entire tooth (crown and root) and supporting bone
There are 2 methods to obtain the images
1. Paralleling technique and Bisecting technique
intraoral examination
B. Bitewing- is where the inter proximal of the teeth surfaces are examined
Includes the crowns of maxillary and mandibular teeth, interproximal areas and areas of crestal bone on the same image
also known as Interproximal Technique
Primarly used to detect interproximal caries, assess existing restorations and examine the crestal bone levels between teeth
C. Full mouth series- is defined as a series of intra oral dental images that show all the tooth-bearing areas of both jaws
Consists of Periapical images alone or a combination of periapical and bitewing images
Bite-wing images should be prescribed only in area where teeth have inter proximal contact with other teeth to examine the contact area for caries (decay)
Also known as Complete mouth series (CMS) or (FMS, FMX)
D. Occlusal- is used to inspect large areas of the maxilla or the mandible on one image
Intraoral examination
E. Panoramic- used to examine the upper and lower jaws and surrounding structures on a single projection
Is considered an Extra oral technique
Also known as rotational panoramic imagining
F. Cephlametric- Exhibits the bony and soft tissue areas of the facial profile
G. CBCT (cone-beam computed tomography)- uses a cone- shaped x-ray beam to aquire information and present it in three dimension
is a computer assisted digital imaging in dentistry
Identify survey used to examine or view specific conditions, teeth or landmarks.
Full Mouth survey
B. Technique
Review patient medical and dental histories for contraindications, including medications.
Intraoral techniques, including error correction
A. paralleling- Is a technique used to obtain periapical images, in which the receptor is placed in the mouth parallel to the long axis of the tooth and the central ray is directed perpendicular to the receptor and the long axis of the tooth, in which the receptor must be placed away from the tooth and toward the middle of the oral cavity
Also known as the Extension- cone paralleling [XCP], right-angle, and long-cone technique)
Some errors that can occur
Receptor Placement
inadequate coverage of the area to be examined radiographically (which is caused by the patient who has a difficulty maintaining or tolerating the receptor placement)
The receptor must be placed straight or perpendicular with the occlusal plane or placed farther away from the teeth to avoid this error. (to not have the image look crooked
B. Bisecting angle- used to expose periapical receptors
Receptor is placed along lingual surface of the tooth. the central ray of the x-ray beam is directed perpendicular to the imaginary bisector formed by the receptor and the long axis of the tooth. Receptor holder is used to stabilize the receptor
Also known as bisecting technique or bisection of the angle technique
It is based on a simple geometric principle known as the Rule of Isometry
The angulation of the PID is critical for this technique
Some errors that can occur
With incorrect horiztonal angulation results in overlapped (unopened) contact areas
With incorrect vertical angulation results in a image that is not of the same length as that of the tooth instead there is distortion and it can either appear longer or shorter. (Elongated or Forshortened images are not diagnositc)
Extraoral technique, inclusing error correction
A. panoramic- shows a wide view of the maxilla and the mandible and surrounding structures
Also known as a rotational Panoramic imaging
Panoramic imagining is used to
evaluate the dentition and supporting structures
evaluate impacted teeth
evaluate eruption pattern, growth, and development
detect diseases, lesions, and conditions of the jaws
examine the extent of large lesions
evaluate trauma
Errors-
Ghost images- is a radiopaque artifact seen on a panoramic image
is if all metallic or dense objects (eyeglasses, earring, necklaces, intraoral and extraoral piercings, hairpins, removable partial dentures, complete dentures, orthodontic retainers, hearing aids, napkin chains) are not removed before the exposure
Lead apron- If placed on incorrectly a radiopaque cone-shape artifact results that obscures diagnostic information
If it is used with a thyroid collar a bilateral radiopaque artifact results that obstructs the mandible
Positioning of lips and tongue- If the patients lips are not closed on the bite-block during the exposure a dark radiolucent shadow results that obscures anterior teeth
Area of increased darkness occurs over the maxillary anterior region and may be mistaken for bone loss.
If tongue is not in contact with the palate during the exposure a dark radiolucent shadow
Obscures the apices of the maxillary teeth
If Chin is tipped up to high
The condyles may not be visible or may appear near the lateral edge of the image
the hard palate and floor of the nasal cavity appear superimposed over the roots of the maxillary teeth
A loss of detail occurs in the maxillary incisor region
A “reverse smile line” (curved downward is seen on the image)
If chin is tipped down to low
The condyles are positioned higher on the image
The hyoid bone forms a single widened line
the mandibular incisors appears blurred; roots may appear short
a loss of detail occurs in the anterior apical region
an “exaggerated smile line” or “jack o lantern” appearance (curved upward)
If the patient is positioned such that the anterior teeth are not positioned in the focal trough (biteblock) and are to forward the teeth can appear blurred or “skinny” and out of focus on the image
It the patient’s anterior teeth are not positioned in the focal trough (biteblock) the teeth appear blurred and are to far back it can appear “fat” and out of focus and the roots of the anterior teeth can appear to be cut off
B. Cephlaometric
C. CBCT (cone-beam computed tomography) basics
Technique modifications based on anatomical variations and clinical conditions
Purpose and maintenance of radiographic equipment
Patient management techniques before, during and after exposure
Mount Images using facial (buccal and labial) view.
A. Anatomical Landmarks that aid in mounting
B. Match tooth views to tooth mount windows
C. Image viewing techniques
Anatomical structures and dental materials observed on images (e.g, differentiating between radiolucent and radiopaque areas)
Features of a diagnostically acceptable image
Prepare images for legal requirements, viewing, duplication and Transfer (e.g, HIPAA)
Radiation safety (25%)
A. X-Radiation production
source of x-radiation for operators/ other staff during x-radiation production
Scatter radiation from the patient which is received during the lateral view
Factors affecting x-ray production (e.g, kVp, mA, Exposure time)
Kilovoltage- Increased kVp produces x-rays with increased energy, shorter wavelength and increased penetrating power; which as well affects the density and contrast
Milliamperage- increased mA produces and increased number of x-rays and affects density
Exposure time- Same as mA affects the number of x-rays produced. A longer exposure time produces more x-rays
The intensity is the total area in the x-ray beam in a specific area at a given time and can affect much more (kVp, mA, distance)
X-radiation Characteristics
Includes x-ray beam quality, quantity, intensity, density, contrast, sharpness, magnification and distortion
X-radiation Physics
Primary- Refers to the penetrating x-ray beam that is produced at the target of the anode and that exits the tube head. (can also be referred to as primary beam or useful beam)
Secondary- Referes to x-radiation that is created when the primary beam interacts with matter. (Secondary radiation is less penetrating than primary radiation)
Scatter- is a form of secondary radiation and is the result of an x-ray that has been deflected from its path by the interaction with matter. ( it is deflected in all directions by the patients tissues and travels to all parts of the of the patients body and to all areas of the dental operators)
(Scatter radiation is detrimental (harmful) to both the patient and the radiographer)
X-radiation biology
Short and long term effects of x-radiation on cells and tissues
Short term- Are effects that are seen within minutes, days or weeks and are associated with large amounts of radiations absorbed in a short amount of time
Effects include Nausea, Vomiting, Diarrhea, hair loss, and hemorrhage
Long term- Are effects that appear after years, decades or generations and are associated with small amounts of radiation that are absorbed in a short amount of time
Effects include cancer, birth abnormalities, and genetic defects
Concepts of x-radiation dose
B. X-Radiation safety
Causes of unnecessary exposure to x-radiation:
Are caused by an improper examination which there is included a predetermine number of images or the images that the patient is being exposed to is a predetermine time interval
Patient exposure to x-radiation (ALARA, ADA recommendations)
ALARA(as low as reasonably achievable)- states that all exposure to radiation must be kept to a minimum
ADA-
Factors that influence x-radiation safety (e.g, filtration, shielding, collimation, PID length)
Filtration- There are 2 kinds of Filtration (Inherent and Added)
Inherent Filtration- takes place when the primary beam passes through the glass window of the x-ray tube, the insulating oil, and the tube-head seal (it alone does not meet the standards regulated by state and federal law)
Added Filtration- is referring to the placement of the aluminum disks in the path of the x-ray beam between the collimator and the tube-head seal in the dental x-ray machine
Shielding- Adequate shielding can greatly reduce the occupational exposure of the dental radiographer such as (protective barriers)
Collimation- is used to restrict the size and shape of the x-ray beam and to reduce patient exposure
PID length- (position-indicating device) appears as an extension of the x-ray tube head and is used to direct the x-ray beam (short 8-inch) (long 16-inch)
Patient x-radiation concerns
Patient education- answer all the patients questions/ concerns ensure them everything is okay
Patient feels more comfortable talking to assistant than doctor since they are the ones completing the procedure
Give patients a pamphlet for them to read and get more information
Reassure a patient that there is state/ federal laws that need apply with being able to work a x-ray machine and as well for everyones safety
Informed consent of patient refusal for exposure to x-radiation
Dentist hold responsibility but the assistant can also ask for permission
Before the patient consents they must know-
risks/ benefits of radiographic procedures
The person responsible for performing the imaging procedure
the # and type of images used
the possible harm that may result in if dental images are not taken
Risks associated with x-ray exposure
alternating diagnostic aids that may serve the same info as x-rays
Disclosure- The process of informing the patient
about the particulars of exposing dental images
Informed Consent- is consent given by the patient which is then followed by complete disclosure
Liability- Dentists are legally accountable or liable to supervise the performance of dental auxiliaries
understand laws, the supervising dentist is legally responsible for actions of their employees (the assistants can still be held accountable for their actions)
Patient refusal-
if the patient refuses the dentist must decide wether an accurate diagnosis can be made and treatment provided without a dental image (in most cases if a patient refuses of the dental images it compromises the patients diagnosis and treatment and the dentist cannot treat the patient
No document can be signed that totally releases dentist from liability (legally the patient cannot consent to negligent care, such consent is invalid)
state in the patient record if they are refusing the recommendation of radigraphs
Protocol for suspected x-ray machine malfunctions
Infection Prevention and Control (25%)
A. Standard precautions for equipment and supplies according to ADA, CDC and OSHA, including but not limited to:
Breakdown and setup of treatment room
Before the procedure gather all the supplies to decrease cross contamination
If you need additional supplies use gloves to grab your additional supplies or ask for some assistance
Always open the sterilization bags in front of the patient so they know that it is sterilized
Barries-
Position devices
Clinical contact surfaces
critical and semi-critical instrument sterilization
Critical Instruments- instruments that are used to penetrate soft. tissue or bone (which must be sterilized after use)
Example- Forceps, scalpels, bone chisel, scalers and surgical burs
which in this case no critical instruments are used in dental imaging
Semi-critical instruments- instruments that contact but do not penetrate the soft tissue or bone
Example- beam alignment (which is used in dental imaging)
Noncritical instruments- are devices that do not come in contact with mucous membranes since they have a little risk of transmitting infection
Example- Position indicating device (PID), dental x-ray tube-head, exposure button, x-ray control panel, lead apron, computer keyboard/ mouse
B. Standard precautions for patient and operators according to ADA,CDC and OSHA, including but not limited to
hand hygiene- Routine hand washing, antiseptic hand wash, and antiseptic hand-rub technique
Before and after treating each patient ( before and after glove placement)
After removing gloves that are torn, cut or punctured and before putting on new gloves
after having contact of bare hands with inanimate objects (blood, saliva, or respiratory secretions)
before leaving the dental operatory
when hands are visibly soiled or contaminated
PPE ( donning, doffing)- All dental professionals must wear protective clothing ( gown, lab coat, uniform)
Donning- to put on and use PPE properly to achieve the intended protection and minimize the risk of exposure
Doffing- to remove the PPE in a way that avoids self-contamination
Cross contamination- the process by which bacteria or other microorganisms are unintentionally transferred from one substance or object to another with harmful effect.
Dispose of all contaminated items in the standard method (always having gloves on when disposing of contaminated items
Use hospital grade surface disinfectant approved by the enviromental protection agency (EPA)